Workers (construction workers, roofers, etc.) who work on elevated and/or inclined surfaces have relatively higher incidences of deaths/injuries due to falls than other work related causes. This five year study provides an experimental design which has the potential for investigating the interaction between work experience of working on elevated and/or inclined surface, age, sex, and other fall risk factors such as physical workload, standing surface inclination and environmental lighting. A series of experiments will be carried out with 240 industrial workers (such as roofers, glazers, painters, ironworkers, etc) with and without experience in working on inclined and/or elevated surfaces to test the following hypotheses: a). There will be a difference in workload induced changes in visual spatial perception abilities between the "experienced" workers and the "inexperienced" workers. b). The experienced workers will have smaller numbers of errors in detecting vertical/horizontal cues after exposure to a workload or while standing on an inclined surface, compared to those from inexperienced workers. c). The workload and poor environmental lighting will have detrimental effects (increase in postural sway variables and/or increase in susceptibility to loss of balance as described by appropriate variables in this application later) on inexperienced workers ability to maintain upright postural balance while performing simulated industrial tasks, as compared to experienced workers. d). The highest level of (100 watts) workload and poor environmental lighting either individually and/or collectively will increase the muscular contraction levels needed to maintain upright balance while performing simulated industrial tasks on inclined surfaces. The experienced workers will show lower levels of postural muscular contractions compared to those with no experience. e. The strategically placed visual cues will significantly improve workers ability to maintain upright balance after exposure to the highest workload (100 watts) and poor environmental lighting and lower the levels of muscular contractions of the postural muscles. As no quantitative data regarding the characteristics of postural balance of experienced workers exists the proposed study is designed to collect such data. Availability of such data will allow to 1) develop planned training programs for new workers who have to perform physically demanding tasks on inclined/elevated surfaces 2) to determine the need of visual cues to minimize excessive postural muscle fatigue and provide a safe upright balance maintenance while working on an inclined and/or elevated surfaces.